From 414d32027632a49fb239abb8fbbb55d3fa8dd861 Mon Sep 17 00:00:00 2001
From: Brent Murphy <56412096+bm11100@users.noreply.github.com>
Date: Thu, 8 Apr 2021 14:28:21 -0400
Subject: [PATCH] [Rule Tuning] Local Scheduled Task Commands (#1043)

* Update persistence_local_scheduled_task_commands.toml
Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>
Co-authored-by: Samirbous <64742097+Samirbous@users.noreply.github.com>
---
 ...istence_local_scheduled_task_commands.toml | 41 -------------
 ...istence_local_scheduled_task_creation.toml | 57 +++++++++++++++++++
 2 files changed, 57 insertions(+), 41 deletions(-)
 delete mode 100644 rules/windows/persistence_local_scheduled_task_commands.toml
 create mode 100644 rules/windows/persistence_local_scheduled_task_creation.toml

diff --git a/rules/windows/persistence_local_scheduled_task_commands.toml b/rules/windows/persistence_local_scheduled_task_commands.toml
deleted file mode 100644
index e6182cd21..000000000
--- a/rules/windows/persistence_local_scheduled_task_commands.toml
+++ /dev/null
@@ -1,41 +0,0 @@
-[metadata]
-creation_date = "2020/02/18"
-maturity = "production"
-updated_date = "2021/03/03"
-
-[rule]
-author = ["Elastic"]
-description = "A scheduled task can be used by an adversary to establish persistence, move laterally, and/or escalate privileges."
-false_positives = ["Legitimate scheduled tasks may be created during installation of new software."]
-from = "now-9m"
-index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
-language = "kuery"
-license = "Elastic License v2"
-name = "Local Scheduled Task Commands"
-risk_score = 21
-rule_id = "afcce5ad-65de-4ed2-8516-5e093d3ac99a"
-severity = "low"
-tags = ["Elastic", "Host", "Windows", "Threat Detection", "Persistence"]
-timestamp_override = "event.ingested"
-type = "query"
-
-query = '''
-event.category:process and event.type:(start or process_started) and
-  process.name:schtasks.exe and
-  process.args:(-change or -create or -run or -s or /S or /change or /create or /run)
-'''
-
-
-[[rule.threat]]
-framework = "MITRE ATT&CK"
-[[rule.threat.technique]]
-id = "T1053"
-name = "Scheduled Task/Job"
-reference = "https://attack.mitre.org/techniques/T1053/"
-
-
-[rule.threat.tactic]
-id = "TA0003"
-name = "Persistence"
-reference = "https://attack.mitre.org/tactics/TA0003/"
-
diff --git a/rules/windows/persistence_local_scheduled_task_creation.toml b/rules/windows/persistence_local_scheduled_task_creation.toml
new file mode 100644
index 000000000..a326f2dac
--- /dev/null
+++ b/rules/windows/persistence_local_scheduled_task_creation.toml
@@ -0,0 +1,57 @@
+[metadata]
+creation_date = "2020/02/18"
+maturity = "production"
+updated_date = "2021/03/15"
+
+[rule]
+author = ["Elastic"]
+description = "A scheduled task can be used by an adversary to establish persistence, move laterally, and/or escalate privileges."
+false_positives = ["Legitimate scheduled tasks may be created during installation of new software."]
+from = "now-9m"
+index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Local Scheduled Task Creation"
+risk_score = 21
+rule_id = "afcce5ad-65de-4ed2-8516-5e093d3ac99a"
+severity = "low"
+tags = ["Elastic", "Host", "Windows", "Threat Detection", "Persistence"]
+timestamp_override = "event.ingested"
+type = "eql"
+
+query = '''
+sequence with maxspan=1m
+  [process where event.type != "end" and
+    ((process.name : ("cmd.exe", "wscript.exe", "rundll32.exe", "regsvr32.exe", "wmic.exe", "mshta.exe",
+                      "powershell.exe", "pwsh.exe", "WmiPrvSe.exe", "wsmprovhost.exe", "winrshost.exe") or
+    process.pe.original_file_name : ("cmd.exe", "wscript.exe", "rundll32.exe", "regsvr32.exe", "wmic.exe", "mshta.exe",
+                                     "powershell.exe", "pwsh.exe", "WmiPrvSe.exe", "wsmprovhost.exe",
+                                     "winrshost.exe")) or
+    process.code_signature.trusted == false)] by process.entity_id
+  [process where event.type == "start" and
+    (process.name : "schtasks.exe" or process.pe.original_file_name == "schtasks.exe") and
+    process.args : ("/create", "-create") and process.args : ("/RU", "/SC", "/TN", "/TR", "/F", "/XML") and
+    /* exclude SYSTEM SIDs - look for task creations by non-SYSTEM user */
+    not user.id : ("S-1-5-18", "S-1-5-19", "S-1-5-20")] by process.parent.entity_id
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1053"
+name = "Scheduled Task/Job"
+reference = "https://attack.mitre.org/techniques/T1053/"
+
+[[rule.threat.technique.subtechnique]]
+id = "T1053.005"
+name = "Scheduled Task"
+reference = "https://attack.mitre.org/techniques/T1053/005/"
+
+
+
+[rule.threat.tactic]
+id = "TA0003"
+name = "Persistence"
+reference = "https://attack.mitre.org/tactics/TA0003/"
+